Abstract

Some species in the genus Pyronota are known to be serious pests of pasture. The establishment of new dairy pastures on recently flipped soils on Cape Foulwind, Buller provided a unique opportunity to investigate the flight behaviour and biology of Pyronota festiva and P. setosa from 2008–2012. Flight behaviour was monitored by fixed-vane interruption traps and by field observations. Adults of both species flew through late spring/early summer (Nov–Dec) of each year and seasonal flight timing was consistent between years. Pyronota festiva flight timing and duration were similar to those previously reported in the literature and were slightly female dominated. Pyronota setosa flights started one to two weeks in advance of P. festiva and were dominated by males (>95%). Female P. setosa were rarely observed flying and were rarely caught in sweep-net sampling. Pyronota setosa beetles were never observed swarming or congregating and feeding on the foliage of mānuka. These differences in flight behaviour may help to explain the field observations that P. festiva can rapidly invade new pastures while P. setosa populations appear to spread more slowly.